It is known in the art relating to engines, such as two cycle diesel engines, to provide an exhaust driven turbocharger (turbo) for supplying scavenging and charging air to the cylinders at above ambient pressures during operation at higher loads and speeds. A gear train may also be provided to drive the turbocharger at lower speeds and loads during which the engine exhaust energy is insufficient to maintain a turbo rotational speed adequate to deliver the required air supply. U.S. Pat. Nos. 3,667,214 Addie and 4,445,337 McCreary disclose two prior arrangements for gear driven turbochargers of this type. Both of these disclosures represent modifications of turbocharger drive arrangements which have been used extensively in diesel-electric railway locomotive engines produced by the Electro-Motive Division of General Motors as well as in numerous other applications of such engines.